I've got GMC chrome wheels from the year 2000, running a set of modern Uniroyal steel belted radial 235/70R-16's if I remember right. That alone made it feel like I wasn't taking my life in my hands over 45mph.
I have the same rear end ratio as you, and picked up a small tach and mounted it to the steering column. It is electronic, so it wires up to the distributor.
According to my tach, at 68 mph, I'm running about 3500 to 3600 rpm. I dared not rev it above 3800 rpm, even though with the Holley/Webber carb, it wanted to. And that took me to short bursts of speed at 70 to 72 mph, so that I could ALMOST keep up with traffic.
My 235's got a crack in it. Still runs, but I only can drive it a few miles at a time with fresh (cheap) oil in it, because after 5 miles, it's mixed with water. I could re-sleeve the block, but it's not worth the money I'd have to spend to rebuild it. So I'm trading my 235 for a Napco 4WD set up.
I'm currently planning on building a 400 for it. I thought about converting it to a 292, and that would be cool too, but I already have a spare 400 motor, sitting in storage. For rear gearing, I'd like to get something taller. Probably a 3.73, because even with a V8, 4000 rpm at 75 mph is really buzzing the motor.
